I dunno man, I guess we will just see if he has it checked out. maybe its a chuckee cheese token, but....... its only .585 fineness gold, so that makes it around 14karat standards, little over 50%, and I have seen rings get water damage and chlorine stress (and its been in a sewer). this isnt a lake or a beach, its been subject to whatever water purifiers and chemicals are flowing through the sewer along with the filth. it may have just led a real rough life. Im on the fence but swinging for gold.
edit- and it couldve been dragged along the bottom of a sewer current across a lot of concrete too, since I imagine it sat ont he bottom the entire time it was down there....go drag your ring across your entire driveway and see how it ends up afterward